High performance cable termination

ABSTRACT

A cable assembly comprising a termination with at least one conductive, compressible member and a conductive ground shield. The conductive, compressible member may be held within a connector module forming the termination such that the conductive compressive member is pressed against, and therefore makes electrical contact with, both an outer conductive layer of the cable and ground structures within the connector module. In some embodiments, these connections may be formed using a conductive, compressible member with an opening configured to receive the end of the cable therethrough. The conductive ground shield may be configured to compress the conductive, compressible member, and to cause the conductive, compressible member to electrically contact the cable&#39;s conductive layer. The conductive, compressible member may be formed from a compressible material and may comprise a plurality of conductive particulates configured to provide electrically conductive paths.

RELATED APPLICATIONS

This Application is a continuation of U.S. patent application Ser. No.16/391,013, filed Apr. 22, 2019, and entitled “HIGH PERFORMANCE CABLETERMINATION,” which is a continuation of U.S. application Ser. No.15/610,376, filed May 31, 2017, and entitled “HIGH PERFORMANCE CABLETERMINATION,” which claims priority to and the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 62/343,625, filedon May 31, 2016, and entitled “HIGH PERFORMANCE CABLE TERMINATION.” Theentire contents of these applications are incorporated herein byreference in their entirety.

BACKGROUND

This patent application relates generally to electrical cables used totransmit signals between electronic devices, such as servers androuters.

Cables are often terminated at their ends with electrical connectorsthat mate with corresponding connectors on the electronic devices,enabling quick interconnection of the electronic devices.

A cable provides signal paths with high signal integrity, particularlyfor high frequency signals, such as those above 40 Gbps using an NRZprotocol. Each cable has one or more signal conductors, which issurrounded by a dielectric material, which in turn is surrounded by aconductive layer. A protective jacket, often made of plastic, maysurround these components. Additionally the jacket or other portions ofthe cable may include fibers or other structures for mechanical support.

The components of the cable that predominately impact signalpropagation, i.e., the signal conductor, the dielectric and conductivelayer, are generally uniform over the length of the cable.Non-uniformities on a signal path, such as might be created by changesin shape or material of the components, give rise to changes inimpedance or promote mode conversion, which reduce signal integrity, asthese effects are manifested as insertion loss, crosstalk or otherundesirable effects.

The signal conductor, dielectric and conductive layer are flexible,giving rise to a desirable property of cables. The flexibility enablesuniform cable properties to be maintained even if the cable is routedwith many bends, promoting signal transmission with high integrity.

One type of cable, referred to as a “twinax cable,” is constructed tosupport transmission of a differential signal and has a balanced pair ofsignal wires, is embedded in a dielectric, and encircled by a conductivelayer. In addition to uniform dimensions of the signal wires over thelength of the cable, the spacing of the wires relative to each other andto the conductive layer is maintained over the length of the cablebecause those components are positioned by the dielectric. Such a cablemay be formed by extruding the dielectric around the signal wires.

The conductive layer is usually formed using foil, such as aluminizedMylar, or wire braid wrapped around the surface of the dielectric. Theconductive layer influences the characteristic impedance in the cableand provides shielding that reduces crosstalk between signal conductorsin twinax cables that may be routed together as a cable bundle. Theconductive layer also forms the cable ground reference.

A twinax cable can also have a drain wire. Unlike a signal wire, whichis generally coated with a dielectric to prevent electrical contact withother conductors in the cable, the drain wire may be uncoated so that itcontacts the conductive layer at multiple points over the length of thecable. At an end of the cable, where the cable is to be terminated to aconnector or other terminating structure, the protective jacket,dielectric and the foil may be removed, leaving portions of the signalwires and the drain wire exposed at the end of the cable. These wiresmay be attached to a terminating structure, such as a connector. Thesignal wires may be attached to conductive elements serving as matingcontacts in the connector structure. The drain wire may be attached to aground conductor in the terminating structure. In this way, any groundreturn path may be continued from the cable to the terminatingstructure.

SUMMARY

According to one aspect of the present application, a cable assembly isprovided. The cable assembly may comprise a cable comprising an end, andan electrical termination. The electrical termination may comprise aconductive ground shield enclosing, at least in part, the end of thecable, and a conductive, compressible member disposed between, and inelectrical contact with, the end of the cable and the conductive groundshield.

According to another aspect of the present application, an electricalconnector is provided. The electrical connector may comprise a pluralityof cable assemblies disposed in one or more columns, each one of theplurality of cable assemblies comprising an electrical termination for acable, the cable comprising an end. The electrical termination maycomprise the end of the cable, a conductive ground shield enclosing, atleast in part, the end of the cable, and a conductive, compressiblemember disposed between, and in electrical contact with, the end of thecable and the conductive ground shield.

According to yet another aspect of the present application, a method forterminating an electrical cable with an electrical terminationcomprising a conductive, compressible member is provided. The method maycomprise inserting an end of the electrical cable in an opening in theconductive, compressible member, the end of the cable comprising anexposed conductive layer surrounding at least one signal conductor. Themethod may further comprise securing a first portion of a conductiveground shield to a second portion of the conductive ground shield withthe first portion contacting a first side of the conductive,compressible member and the second portion of the conductive groundshield contacting a second side of the conductive, compressible membersuch that the conductive, compressible member is compressed between thefirst portion and the second portion of the conductive ground shield soas to make electrical connection between the conductive layer and theconductive ground shield.

According to yet another aspect of the present application, a connectormodule for terminating a cable with an outer perimeter is provided. Theconnector module may comprise a conductive, compressible member havingan opening there through, the opening being sized to have, in anuncompressed state, an interior perimeter greater than the outerperimeter of the cable and, in a compressed state, an interior perimeterless than or equal to the outer perimeter of the cable, and a conductiveground shield contacting and enclosing, at least in part, theconductive, compressible member.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1A is an isometric view of an electrical cable including a drainwire;

FIG. 1B is an isometric view of a connector configured to operate inconnection with the electrical cable of FIG. 1A;

FIG. 2A is an exploded view of an exemplary cable assembly comprising aconductive, compressible member, in accordance with some embodiments;

FIG. 2B is a cross sectional view of an exemplary electrical cable, inaccordance with some embodiments;

FIG. 3 is an isometric view of an exemplary conductive, compressiblemember, in accordance with some embodiments;

FIG. 4 is a scanning electron microscope (SEM) image illustrating aconductive, compressible material comprising a plurality of conductiveparticulates, in accordance with some embodiments;

FIG. 5A is an isometric view of the cable assembly of FIG. 2A in apartially assembled configuration, in accordance with some embodiments;

FIG. 5B is an isometric view of the cable assembly of FIG. 2A in a fullyassembled configuration, in accordance with some embodiments;

FIG. 6 is an exploded view of another exemplary cable assemblycomprising a conductive, compressible member, in accordance with someembodiments;

FIG. 7A is an isometric view of the cable assembly of FIG. 6 in apartially assembled configuration, in accordance with some embodiments;

FIG. 7B is an isometric view of the cable assembly of FIG. 6 in a fullyassembled configuration, in accordance with some embodiments;

FIG. 8 is an isometric view of a cable module, in accordance with someembodiments;

FIG. 9 is an isometric view of an interconnection system comprising aplurality of cable assemblies, in accordance with some embodiments.

FIGS. 10A-10C illustrate a conductive ground shield having a conductive,compressive member attached thereon, in accordance with someembodiments.

FIGS. 11A-11B illustrate a cable assembly forming a void which may befilled, at least partially, with a conductive, compressive member, inaccordance with some embodiments.

DETAILED DESCRIPTION

The inventors have recognized and appreciated that a conductive,compressible member used in a cable termination may provide a highperformance cable interconnection system. The conductive, compressiblemember may be positioned between a conductive layer of a cable and aconductive member on a terminating structure, such as a connector. Anyjacket or insulating covering on the conductive layer may be removed atthe cable termination such that the conductive, compressible member maymake an electrical connection to both the conductive layer of the cableand the conductive member of the terminating structure.

The conductive member, the conductive layer, and the conductive,compressible member may be mounted so that the conductive, compressiblemember is compressed between the conductive member and the conductivelayer. The compression may create a reliable electrical connectionbetween the conductive layer of the cable and the conductive,compressible member of the terminating structure via the conductive,compressible member. When compressed between the conductive member andthe conductive layer, the conductive compressible member may form acontact with the conductive layer of less than 100 Ohms in someembodiments, less than 75 Ohms in some embodiments, less than 50 Ohms insome embodiments, less than 25 Ohms in some embodiments, less than 10Ohms in some embodiments, less than 5 Ohms in some embodiments or lessthan 1 Ohm in some embodiments. When compressed between the conductivemember and the conductive layer, the conductive compressible member mayform a contact with the conductive layer of at least 0.5 Ohms in someembodiments, at least 1 Ohm in some embodiments, at least 5 Ohms in someembodiments, at least 10 Ohms in some embodiments, at least 25 Ohms insome embodiments or at least 50 Ohms in some embodiments. In suchembodiments, the connection may be suitable for grounding.

The compressive force may be created by members in the terminatingstructure, which may be a separate structure or may be the conductivemember. In some embodiments, the conductive member may be a portion of astructure that encircles the cable termination with a perimeter smallerthan the uncompressed perimeter of the conductive, compressible member.

In some embodiments, the terminating structure may be a cable connector,or a portion of a cable connector, and the conductive member may be areference conductor or shielding member in the cable connector. As aspecific example, the portion of the cable connector may be a module,holding a pair of signal conductors encircled by the conductive element.Multiple such modules may be positioned in an array to form a connectorterminating a cable bundle.

Electrical terminations of the type described herein may be configuredto terminate any suitable type of electric cable, such as twinax cablesand coax cables.

The conductive element may be a portion of a multi-piece shell thatencircles at least the cable termination of the module. That multi-pieceshell may be conductive, forming shielding for the module.

In some embodiments, the conductive, compressible member may be aconductive elastomer. A conductive elastomer may be formed by addingconductive filler to an elastomer. In some embodiments, the elastomermay be configured to elongate by a percentage that is at least 90%. Insome embodiments, the elastomer may be configured to elongate, withoutbreaking, by a percentage that is less than 1120%. The elastomer, forexample, may be a silicone rubber. The filler may be particles in anysuitable form, including plates, spheres, fibers, or of any othersuitable geometry. As a specific example, the conductive, compressiblemember may be made of silver-plated glass micro spheres suspended inhigh consistency rubber (HCR) silicone.

The filler may comprise a sufficient portion of the conductive,compressible member such that there is contact between conductivefillers when the conductive, compressible member is compressed. Such aconductive, compressible member may be formed by filling an elastomer orother suitable compressible matrix with conductive fillers at a volumepercentage between 25% and 95% in an uncompressed state, in someembodiments. In some embodiments, the volume percentage may be between45% and 90% or between 60% and 90%.

In some embodiments, the fillers may be of materials or present in anamount that results in a bulk resistivity in a range of 10⁻⁶ ohm-cm to10⁻¹ ohm-cm.

Cable assemblies, using a conductive, compressible member as part of atermination as described herein, may use cables without drain wires.Such cable assemblies may be lighter and more flexible. Moreover, theuse of such cable assemblies may simplify the operation for terminatingthe cable.

FIG. 1A illustrates a conventional electrical cable. Electrical cable10, also referred to as “twinax cable”, comprises signal wires 11 and12, which are covered by dielectric coating 13 and 14 respectively. Thecable further comprises a third, uncovered wire 15, referred to as“drain wire”. Signal wires 11 and 12 and drain wire 15 are surrounded byconductive layer 16, which is configured to serve as an electric shield.The drain wire 15 electrically contacts the conductive layer 16 atmultiple locations along the cable (not shown), thus maintaining aground reference with the conductive layer. As illustrated in FIG. 1A,the enclosing jacket and the conductive layer have been removed from theend of the cable to permit termination.

FIG. 1B illustrates a connector 90 configured to receive one or morecables 10. Connector 90 comprises a circuit board 98 and groundingportion 95. Grounding portion 95 includes a plurality of openings 96,each configured to receive a cable 10. When a cable 10 is inserted intoan opening 96, signal wires 11 and 12 form electrical contacts withcontact portions 93. Furthermore, grounding portion 95 includes aplurality of slots 97, each slot being configured to receive therein thedrain wire of the corresponding cable 10. The grounding portion maycontact the various drain wires, thus keeping the cables grounded. Whilethe use of drain wires ensures signal integrity throughout the length ofthe cable, having to include an additional wire may add weight andreduce the flexibility of the cable.

According to one aspect of the present application, the flexibility ofthe cables and the cost associated with the termination of the cablesmay be reduced by using electrical terminations comprising a conductive,compressible material. FIG. 2A is an exploded view of a cable assembly,in accordance with some embodiments. Cable termination 20 may comprisethe end of a cable 202, a conductive, compressible member 210, adielectric member 220, and conductive ground shield portions 230 and232.

Cable termination 20 may mate with a connector mounted in an electronicdevice. For example, the connector may be mounted on a printed circuitboard (PCB) in an electronic device. The opposite end of cable 202 maybe similarly configured to mate with another electronic device. Cable202 may be configured to connect any suitable electronic device to anyother suitable device, such a first computer to a second computer, acomputer to a server, or a peripheral device, such as a video card, to amotherboard within a computer. Cable 202 may have characteristicsselected for the types of signals to pass between the connected devices.For example, cable 202 may comprise a pair of signal conductors 204 and206, which may be configured to carry a differential signal in someembodiments. Cable 202 may be configured to support signals having anysuitable electric bandwidth, such as more than 20 GHz, more than 30 GHzor more than 40 GHz.

FIG. 2B is a cross sectional view of cable. As illustrated, signalconductors 204 and 206 may be surrounded by a dielectric material 208,which may be configured to prevent the signal conductors from contactingone another. Alternatively, or additionally, the signal conductors maybe coated with a dielectric material. Signal conductors 204 and 206 maybe formed from copper or from a copper alloy, such as copper-zinc,copper-nickel, copper-magnesium, copper-iron, etc. Dielectric material208 may be enclosed within a conductive layer 209, which may comprise afoil, such as aluminized Mylar foil, or wire braid wrapped around thesurface of the dielectric material. Conductive layer 209 may beconfigured to provide shielding so as to reduce crosstalk betweenadjacent signal conductor pairs. As illustrated, cable 202 may notinclude drain wires in some embodiments.

Referring back to FIG. 2A, cable termination 20 may be configured toterminate cable 202, using conductive, compressible member 210 to forman electrical connection between a ground structure of cable 202 andconductive ground shield portions 230 and 232. Conductive, compressiblematerial 210 may be formed using a material having an elongation rangepercentage that is between 90% and 1120%. In some embodiments,conductive, compressible material 210 may be formed using a materialhaving a tensile strength that is between 4 Mpa and 13 Mpa. In someembodiments, conductive, compressible material 210 may be formed using amaterial having a tear strength that is between 9 kN/m and 55 kN/m. Byway of example and not limitation, conductive, compressible material 210may be formed using silicone, such as silicone rubber. Various types ofsilicone rubber may be employed, including high consistency rubber(HCR), fluorosilicone rubber (FSR), liquid silicone rubber (LSR).Conductive, compressible material 210 may be produced by using avulcanization process, such as room temperature vulcanizing (RTV), andmay be molded into a desired shape.

As illustrated in FIG. 3 , conductive, compressible material 210 may beconfigured to partially or fully encircle cable 202 and to be positionedbetween an outer conductive layer of the cable and grounding structurein the cable connector terminating the cable. In the embodimentillustrated, compressible material is configured as a unitary memberwith an opening 212, which may be configured to receive cable 202therethrough. The opening may have a perimeter large enough to allowcable 202 to fit therein. For example, opening 212 may have a width W₁that is between 0.5 mm and 5 mm in some embodiments, and a height H₁that is between 0.5 mm and 5 mm in some embodiments. Conductive,compressible material 210 may have a width W₂ that is between 1 mm and20 mm in some embodiments, a height H₂ that is between 1 mm and 20 mm insome embodiments, and a length that is between 0.5 mm and 10 cm. Thedimensions of the conductive, compressible member 210 and of the opening212 are solely intended by way of example, and are not limited to theranges provided. The interior perimeter of the opening in anuncompressed state may be greater than the outer perimeter of the cableby at least 0.5% in some embodiments, by at least 1% in someembodiments, by at least 3% in some embodiments, by at least 5% in someembodiments, by at least 10% in some embodiments, by at least 20% insome embodiments or by at least 30% in some embodiments. The interiorperimeter of the opening in an uncompressed state may be greater thanthe outer perimeter of the cable by no more than 5% in some embodiments,by no more than 10% in some embodiments, by no more than 15% in someembodiments, by no more than 25% in some embodiments, by no more than50% in some embodiments, by no more than 75% in some embodiments or byno more than 100% in some embodiments.

Conductive compressible material may be formed in any suitable way. Insome embodiments, conductive, compressive material may comprise acombination of materials, some of which provide desired mechanicalproperties, and others of which provide desired electrical properties.Conductive, compressible material 210 may comprise a polymer or othercompressible material filled with a plurality of conductiveparticulates, configured to collectively form electrically conductivepaths. FIG. 4 is a scanning electron microscope (SEM) image of aconductive, compressible member having a plurality of conductiveparticulates 402 embedded therein. In some embodiments, the conductiveparticulates may comprise microspheres, such as silver-plated glassmicrospheres. Conductive particulates 402 may be disposed so as to formelectrically conductive paths between an inner surface of opening 212and an outer surface of conductive, compressible member 210.

Referring back to FIG. 2A, as part of the process of terminating cable202, cable 202 may be passed through opening 212 of conductive,compressive member 210, such that at least a portion of opening 212encloses conductive layer 209. In some embodiments, each signalconductor may pass through a corresponding channel of dielectric member220. For example, signal conductor 204 may pass though channel 224 andsignal conductor 206 may pass though channel 226. At the end of cable,the signal conductors may extend beyond an end of dielectric member 220.Any suitable approach may be used to configure the end of the cable inthis way. A known technique for terminating a cable is to strip away, atthe end of the cable, components of the cable to expose the signalconductors. In accordance with some embodiments, different componentsmay be stripped away to expose different components of the cable. Forexample, the jacket, a conductive layer and dielectric may be strippedaway at the distal end of the cable to expose signal conductors at thedistal end of the cable. In other regions, only the jacket may beremoved, exposing the conductive layer.

Termination of cable 202 may be performed by contacting conductiveground shield portions 230 and 232 with a first side and a second sideof conductive, compressible member 210 respectively. The ground shieldportions may be integrated into the cable termination so that they pressagainst the conductive, compressible member 210 and may cause acompression of the conductive, compressible member 210. Any suitabletechnique may be used to press one or more ground shield portionsagainst conductive, compressible member 210. In some embodiments, groundshield portions 230 and 232 may be held within a housing. Alternativelyor additionally, ground shield portions 230 and 232 may be secured toeach other, to provide an interior perimeter partially or totallyencircling conductive, compressible member 210. That inner perimeter maybe smaller than an uncompressed outer perimeter of conductive,compressible member 210.

In some embodiments, such compression may cause a reduction in thevolume of the conductive, compressible member 210. In some embodiments,such compression may cause a reduction in the volume of the opening 212.To ensure that there is compression, which aids in making goodelectrical contact, the conductive, compressible member may have anouter perimeter that is greater than an inner perimeter of theconductive ground shield formed from conductive ground shield portions230 and 232. Materials and termination techniques may also be used toaid in electrical connection between conductive, compressible member 210and conductive ground shield portions 230 and 232 or a conductive layerof a cable. The portions of the conductive ground shield portions 230and 232 that contact conductive, compressible member 210 may be treatedsuch that there is little or no oxide on the ground shield portions 230and 232. Such a treatment, for example, may be chemical or mechanical,using known techniques that remove metal oxides. Alternatively oradditionally, the treatment may entail applying gold, nickel, nickel/tinalloys or or other metal that resists oxidation.

While FIG. 2A illustrates a conductive ground shield formed from twoportions, any other suitable number of portions, each having anysuitable shape, may be used. In some embodiments, the conductive groundshield may be configured to further enclose, at least in part,dielectric member 220. Alternatively or additionally, the conductiveground shield may be configured to cover other portions of thetermination in addition to conductive, compressible member 210. Theground shields, for example, may extend to partially or totally encirclemating contact portions of a termination to which signal conductors ofthe cable are attached.

FIG. 5A is an isometric view of the cable assembly of FIG. 2A in apartially assembled configuration, in accordance with some embodiments.In the example illustrated, conductive, compressible member 210 issecured to one side of conductive ground shield portion 232. Conductiveground shield portion 230 is unsecured, but may be secured to conductiveground shield portion 232 using snaps, latches, hubs, bands, or anyother suitable attachment mechanism. In some circumstances, theconductive ground shield portions may be manually pressed together usingfor example, hand tools, such as pliers or wrenches. In othercircumstances, the conductive ground shield portions may be pressedtogether using an automatic assembly machine.

Regardless of how attached, when conductive ground shield portion 230 isattached to conductive ground shield portion 232, as illustrated in FIG.5B, conductive, compressible member 210 is compressed between the cableand the conductive ground shield. As a result of such compression,opening 212 may reduce in size, and conductive, compressible member 210may physically and electrically contact cable 202. In such circumstance,the inner surface of opening 212 may electrically contact conductivelayer 209 of cable 202. Thus, an aspect of terminating cable 202 mayresult be compressing, conductive, compressible member 210 intoelectrical contact with the cable and with the conductive ground shield.

In some circumstances, it may be desirable to control the impedance ofthe electric termination, and impedance control may be achieved by theshape and/or position of conductive, compressible material. For example,impedance at any location along the length of a conductive element maydepend on a distance to a ground conductor, among other factors. Theconductive, compressible material may be shaped and positioned to act asthe closest ground conductor to a signal conductor in the cable orconnector terminating the cable. The conductive, compressible materialmay be shaped to provide the desired spacing between the signalconductors and the ground structure.

FIG. 6 is an exploded view of another exemplary termination of a cableassembly comprising a conductive, compressible member, in accordancewith some embodiments. As in the non-limiting example on FIG. 2A,termination 60 may be configured to terminate cable 602, usingconductive, compressible member 610 and conductive ground shieldportions 630 and 632. Termination 60 may comprise an end of cable 602, aconductive, compressible member 610, a dielectric member 620, and aconductive ground shield. In some embodiments, the conductive groundshield may be formed from conductive ground shield portions 630 and 632.Cable 602 may comprise signal conductors 604 and 606, a dielectricmaterial surrounding the signal conductors and a conductive layer, suchas a foil or wire braid, enclosing the dielectric material, and thesignal conductors (not shown in FIG. 6 ).

In some embodiments, each signal conductor of cable 602 may be connectedto a corresponding conductive portion serving as a mating contact tomate with a signal conductor in a mating connector. For example, signalconductor 604 may be connected to conductive element 605 and signalconductor 606 may be connected to conductive portion 607. The conductiveportions and the signal conductors may be connected by soldering,brazing welding or in any other suitable way.

Conductive, compressive member 610 may comprise an opening 612, whichmay be configured to receive cable 602 therethrough. In contrast to theembodiment of FIG. 3 in which conductive, compressible member 210 isannular with a uniform cross section along the longitudinal direction ofthe cable, conductive, compressive member 610 may have a cross sectionthat is non-uniform. The non-uniform cross section may be configured toincrease the spacing between a centerline of the cable or termination inregions where the signal conductors widen. Conversely, in regions wherethe signal conductors narrow, the interior surfaces of the conductive,compressive member 610 adjacent the signal conductors may get closer tothe center line. Though, it should appreciated be that the distancebetween the interior surfaces of the conductive, compressive member 610and the signal conductors may vary to compensate for any characteristicof the other components of the termination, including thickness of thesignal conductors, dielectric constant of material surrounding thesignal conductors.

In the embodiment illustrated, when assembled, conductive, compressivemember 610 may be configured to contact dielectric member 620, which inthis example represents a housing of a cable connector that supportsmating contact portions of a cable connector. In some embodiments, thecontacting surfaces of conductive, compressive member 610 and dielectricmember 620 may comprise complementary features. For example, asillustrated in FIG. 6 , the contacting surface of dielectric member 620may comprise a projecting member 622, which may be configured to matewith a depression formed on the contacting surface of conductive,compressive member 610. In this configuration, projecting member 622 maybe in contact with conductive, compressive member 610. When termination60 is assembled, cable 602 may pass through opening 612 and conductiveelements 605 and 607 may pass through channels 624 and 626 of dielectricmember 620, acting as a housing for a connector module terminating thecable 602. It should be appreciated that, in the exploded view of FIG. 6, conductive elements 605 and 607 are shown outside of channels 624 and626. In some embodiments, a dielectric member 620 may be formed withchannels 624 and 626 into which conductive elements 605 and 607 aresubsequently inserted. In other embodiments, dielectric member 620 maybe molded around conductive elements 605 and 607, forming channels 624and 626 in the process. In yet other embodiments, two or more dielectricelements might be positioned around conductive elements 605 and 607,forming channels 624 and 626.

Having complementary features formed on the contacting surfaces of theconductive, compressive member 610 and dielectric member 620 maymitigate variations in impedance caused by air gaps forming between thetwo members, which may be the case if conductive, compressive member 610and dielectric member 620 are not properly contacted.

FIG. 7A-7B illustrate termination 60 in a partially assembledconfiguration and in a fully assembled configuration, respectively. Inthe partially assembled configuration shown in FIG. 7A, dielectricmember 620 is shown holding conductive elements 605 and 607, which hereare mating contact portions of signal conductors in a connector moduleterminating cable 602. As illustrated, dielectric member 602 is aunitary structure, such as may be formed by molding dielectric materialaround conductive elements 605 and 607. However, it should beappreciated that a housing of dielectric material may be formed in anysuitable way, including as multiple separate pieces that are heldtogether using snaps, welding, adhesive, interference fit, etc.

As shown in FIG. 7A, conductive ground shield portion 632 is placed incontact with conductive, compressive member 610 and dielectric member620. Signal conductors within cable 602 may pass through opening 612 andelectrically connect to conductive elements 605 and 607. In the fullyassembled configuration, conductive ground shield portion 630 is alsoplaced in contact with conductive, compressive member 610. In thisconfiguration, the conductive ground shield portions may press againstthe conductive, compressive member 610, thus causing it to reduce involume. As a consequence, an inner surface of opening 612 may contactthe conductive layer of cable 602.

However, it should be appreciated that other construction techniquesalternatively or additionally may be used. For example, conductive,compressive member 610 is shown as a unitary structure with an openingto receive a cable. However, it should be appreciated that portions ofthe conductive, compressive material forming conductive, compressivemember 610 may be attached to conductive ground shield portions 630 and632, respectively. The material may be shaped such that, when conductiveground shield portions 630 and 632 are pressed together, the conductive,compressive material encircles cable 602.

In some embodiments, connector modules may be attached to cables,creating cable assemblies that may be used to connect electronicdevices. Each module may comprise one or more conductive, compressiblemembers configured to terminate one or more cables in the mannerdescribed above. A non-limiting example of such module is illustrated inFIG. 8 . The modules may comprise mating contact portions configured tomate with mating contact portions in a mating connector. In theembodiment illustrated, the mating contact portions are pin-shaped, andare configured to mate with mating contact portions in a receptacle. Insome embodiments, multiple modules like module 80 may be held together,side-by-side, to form a connector terminating a cable assembly.

Termination 80 may comprise a module 150, terminating a pair of cables810 and 811, which may be of the type described in connection to FIG.2A, 2B or 6 . Signal conductors in cable 810 may be coupled to matingcontact portions 812 and 814. Signal conductors in cable 811 may becoupled to mating contact portions 816 and 818. The cables may eachcomprise a conductive layer enclosing the signal conductors.

Module 150 may include a housing portion 82. Housing portion 82 may beformed of a dielectric material, and may hold mating contact portions812 and 814. In some embodiments, mating contact portions may be held byhousing portion 82 with ends exposed. Those ends may be attached towires within cables 810 and 811, using techniques such as welding,brazing or soldering. However, the specific attachment technique is notcritical to the invention, and any suitable attachment technique may beused.

Module 150 may comprise a conductive, compressible member of the typedescribed herein. In the embodiment illustrated, member 84 may be formedof a conductive, compressive material. In some embodiments, member 84may be injected in a molding operation into an opening in housingportion 82. In this way, member 84 may be attached to housing portion82. However, other assembly techniques may be used, including insertinga cable into an opening in member 84 or assembling member 84 frommultiple separate pieces of conductive, compressive material. Regardlessof how member 84 is integrated into module 152 it may be positioned tocontact conductive layers exposed on exterior surfaces of cables 810 and811 and grounding structures within module 152. In some embodiments,those grounding structures may be conductive ground shields (not shownin FIG. 8 ) configured to compress the conductive, compressible member.Conductive ground shields, for example, may have planar portionspressing against the exposed surfaces of member 84.

In some embodiments, the conductive, compressible member may also makecontact with conductive elements that form mating contact portions forgrounds of module 150. In the embodiment of FIG. 8 , the mating contactportions of the conductive elements in the module 150, including bothsignal conductors and ground conductors, may be positioned in a column.When like modules are stacked side-by-side, the mating contact portionsmay form a two-dimensional array of mating contact elements, providing aconnector interface.

In some embodiments, signal conductors 812 and 814 may be electricallyconnected to conductive elements 821 and 822, and signal conductors 816and 818 may be electrically connected to conductive elements 824 and825. Conductive elements 820, 823 and 826 may be connected to theconductive layers of cables 810 and 811 via conductive, compressiblemembers disposed in the housing 82, such that conductive elements 820,823 and 826 serve as aground conductors. Such a connection may be formedin any suitable way, including by having conductive elements 820, 823and 826 integrally formed with or attached to grounding structurespressing against portion 84. However, it should be appreciated thatother approaches for making connections using a conductive, compressivematerial may be used. In some embodiments, a conductive compressivemember may be pressed into both a conductive outer layer of a cable anda portion of the conductive elements 820, 823 and 826. For example,portions of conductive elements 820, 823 and 826 within housing 82 maybe widened with respect to the mating contact portions visible in FIG. 8. Those widened portions may be adjacent an outer conductive layer ofcables 810 and/or 811 such, when the conductive compressive member ispressed against the conductive layer of the cable, it is also pressedagainst a portion of conductive elements 820, 823 and 826.

FIG. 9 illustrates an interconnection system comprising a plurality ofelectric terminations of the type described herein. Interconnectionsystem 900 may comprise electrical connector 910 and electricalconnector 960. Electrical connector 910 may comprise a plurality ofcable assemblies 912, which may be implemented using, at one end of thecables, termination 20 or termination 60, or any other suitabletermination.

Each cable assembly 912 may comprise a conductive ground shield 914,which may be configured to compress a respective conductive,compressible member (not shown in FIG. 9 ) when attached to thetermination. Each conductive, compressible member may be shaped tocontact an outer conductive layer of a cable, such as by having anopening which may be configured to receive a respective cable 916therethrough. Each cable 916 may comprise one or more signal conductors.

An opposite end of the cables may also be terminated. The nature of thetermination may depend on the intended use of the cable assemblies. Insome embodiments, the terminations at the opposite end may be the sameas terminations 20 or 60 or other termination as described herein. Inother embodiments, cables 916 may be configured to connect to a circuitboard at a right angle by terminating the other end of the cableassemblies with modules that have contact tails adapted for attachmentto a printed circuit board. In such embodiments, an end of the cable maybe coupled to a connection portion 920, which may comprise a pluralityof conductive tails 930. At least one of the conductive tails may beelectrically connected to the conductive layer of a respective cable.That connection may be made through the use of compressive, conductivematerial as described herein, though any suitable attachment mechanismmay be used. Additional conductive tails may each be electricallyconnected to a signal conductor. However, the application is not limitedin this respect and electrical connector 910 may be configured toconnect to an electronic device in any suitable way.

The cable assemblies of electrical connector 910 may be configured to beinserted into corresponding receptacles of electrical connector 960.Each receptacle may comprise a housing 964. In some embodiments, thehousings 964 may be electrically connected to each other, and may beconnected to a reference potential, such as a ground terminal. Wheninserted into a corresponding receptacle, a conductive ground shield mayelectrically contact an internal surface of a housing 964, thus placingthe cable's conductive layer at the electric potential of the referenceterminal. In some embodiments, a conductive ground shield may compriseone or more conductive tabs 918, which may be configured to bend whenthe cable assembly is inserted in the corresponding receptacle and toelectrically contact a housing 964. Electrical connector 960 may beconfigured to be mounted on a printed circuit board, such as amotherboard, though conductive tails 966.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated that various alterations,modifications, and improvements will readily occur to those skilled inthe art.

For example, a compressive conductive member was illustrated as being aunitary structure with an opening slightly larger than the outer surfaceof a cable with an exposed conductive layer. Such a structure may bereadily formed by extruding conductive compressive material in a tubeand slicing segments of a desired length. However, it is not arequirement that the conductive compressive member be a unitary member,and other manufacturing techniques may be used, including formingseparate pieces of conductive compressive material and adding them to aconnector or molding conductive compressive material onto othercomponents while still in an uncured or partially cured state andallowing the conductive compressive material to cure in place. Such anapproach may be readily implemented with conductive compressive materialimplemented with a silicone matrix or matrix of any other polymer thatmight be cured, such as a result of adding a curing agent, passage oftime, exposure to heat, UV light or other source of energy, or in anyother way.

In some embodiments, conductive, compressive material may be attached toa portion of a cable assembly such that, when the cable is terminated,the conductive compressive material is compresses between the cable'sconductive layer and the conductive ground shield. For example,conductive, compressive material may be attached to the conductiveground shield. FIGS. 10A-10C illustrate a representative configurationin which a conductive, compressive material is attached to a conductiveground shield. In particular, FIGS. 10A and 10B are an isometric viewand an exploded isometric view of a conductive ground shield 1002.Conductive ground shield 1002 may be a unitary piece, or may be formedfrom multiple pieces assembled together. Conductive ground shield 1002is arranged to form an opening 1010 there through. Conductive groundshield 1002 may enclose opening 1010, fully or partially, which may beconfigured to receive a cable therein.

As illustrated, conductive, compressive member 1004 may be connected tothe conductive ground shield 1002, and may at least partially bepositioned inside opening 1010. Conductive, compressive member 1004 maybe attached to conductive ground shield 1002 in any suitable way. Forexample, conductive, compressive member 1004 may be molded ontoconductive ground shield 1002 while still in an uncured or partiallycured state and may be cured in place. Any suitable molding techniquesmay be used, including but limited to two-shot injection molding,extrusion molding, compression molding, transfer molding, thermomolding,blow molding, rotational molding, structural foam molding, shrink wrapmolding, and over molding.

In some embodiments, conductive, compressive material 1004 is attachedto the inner wall of conductive ground shield 1002 (e.g., in opening1010) and to the outer wall, as illustrated in FIG. 10B. Conductive,compressive member 1004 may be made of any one of the materialsdescribed above and may have conductive particulates embedded therein,as described in connection with FIG. 4 . Additionally, or alternatively,conductive, compressive member 1004 may be made of a thermoplasticelastomer, polypropylenes, polyoefins, liquid crystal polymers, orsilicon rubber, among others. Conductive, compressive member 1004 mayhave a surface resistance that is less than 10 Ω/in², in someembodiments.

Conductive, compressive member 1004 may be arranged and sized such that,when conductive ground shield 1002 is mounted with a cable, conductive,compressive member 1004 is compressed between the cable and conductiveground shield 1002. In this way, a conductive path between the cable'sconductive layer and the conductive ground shield may be formed. Forexample, conductive, compressive member 1004 may comprise one or moreprotrusions 1006 extending away from conductive ground shield 1002. Whena cable is received in the opening 1010, protrusion(s) 1006 may bearranged to be compressed between the cable and the shield.

FIG. 10C illustrated a cable 1014 inserted into an opening 1010. Asillustrated, conductive, compressive member 1004 fills, at leastpartially, the space between the cable 1014 and the conductive groundshield 1002. In this way, a conductive path between the cable'sconductive layer 1012 and the shield is formed, thereby terminating thecable. As further illustrated in FIG. 10C, the assembly may be connectedto a connector 1020.

FIGS. 11A-11B illustrate an exemplary cable assembly for use inconnection with termination techniques described. FIG. 11A is anisometric view and FIG. 11B shows the assembly of FIG. 11B where aportion of the conductive ground shield has been removed. Asillustrated, connector 1020 is connected to cable 1014, which isterminated using a conductive ground shield 1002. Connector 1020includes contacts 1100 and 1102. When mated, cable 1014 is in electricalcontact with contacts 1100 and 1102. Cable 1014 and connector 1020 maybe connected via dielectric member 1022.

Conductive ground shield 1002 may be arranged such that a void 1110 isformed between the shield and the cable. In some embodiments, void 1110may be filled, at least partially, with a conductive, compressivemembers of the type described herein (e.g., conductive, compressivemember 210, 610 or 1004). When the cable is assembled with the shield,the conductive, compressive member may contact, physically andelectrically, conductive layer 1012 and conductive ground shield 1002.

As another example, use of conductive, compressive material wasillustrated in connection with specific connector configurations, andparticularly in connection with making connections to a conductive layerof a cable. This approach may be used in other connector structures toconnect members intended to be grounded.

Such alterations, modifications, and improvements are intended to bepart of this disclosure, and are intended to be within the spirit andscope of the invention. Further, though advantages of the presentinvention are indicated, it should be appreciated that not everyembodiment of the invention will include every described advantage. Someembodiments may not implement any features described as advantageousherein and in some instances. Accordingly, the foregoing description anddrawings are by way of example only.

Various aspects of the present invention may be used alone, incombination, or in a variety of arrangements not specifically discussedin the embodiments described in the foregoing and is therefore notlimited in its application to the details and arrangement of componentsset forth in the foregoing description or illustrated in the drawings.For example, aspects described in one embodiment may be combined in anymanner with aspects described in other embodiments.

Also, the invention may be embodied as a method, of which an example hasbeen provided. The acts performed as part of the method may be orderedin any suitable way. Accordingly, embodiments may be constructed inwhich acts are performed in an order different than illustrated, whichmay include performing some acts simultaneously, even though shown assequential acts in illustrative embodiments.

Also, circuits and modules depicted and described may be reordered inany order, and signals may be provided to enable reordering accordingly.

Computer-executable instructions may be in many forms, such as programmodules, executed by one or more computers or other devices. Generally,program modules include routines, programs, objects, components, datastructures, etc. that perform particular tasks or implement particularabstract data types. Typically, the functionality of the program modulesmay be combined or distributed as desired in various embodiments.

Also, data structures may be stored in non-transitory computer-readablestorage media in any suitable form. For simplicity of illustration, datastructures may be shown to have fields that are related through locationin the data structure. Such relationships may likewise be achieved byassigning storage for the fields with locations in a non-transitorycomputer-readable medium that convey relationship between the fields.However, any suitable mechanism may be used to establish relationshipsamong information in fields of a data structure, including through theuse of pointers, tags or other mechanisms that establish relationshipsamong data elements.

Use of ordinal terms such as “first,” “second,” “third,” etc., in theclaims to modify a claim element does not by itself connote anypriority, precedence, or order of one claim element over another or thetemporal order in which acts of a method are performed, but are usedmerely as labels to distinguish one claim element having a certain namefrom another element having a same name (but for use of the ordinalterm) to distinguish the claim elements.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified.

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

What is claimed is:
 1. An electrical termination comprising: aconductive ground shield comprising first and second conductive groundshield portions having respective latches; and an elastomer comprisingan opening therethrough and comprising a plurality of conductiveparticulates embedded therein, the elastomer being disposed between thefirst and second conductive ground shield portions with an end of thecable passing through the opening, wherein the elastomer, in anuncompressed state, has a perimeter that is greater than a perimeter ofthe conductive ground shield, wherein, when the first and secondconductive ground shield portions are latched to one another and enclosethe elastomer, the elastomer presses against the end of the cable. 2.The electrical termination of claim 1, wherein the conductive groundshield individually encloses the cable, and wherein the cable comprisesa single pair of signal conductors.
 3. The electrical termination ofclaim 1, wherein the end of the cable comprises an exposed conductivelayer surrounding signal conductors, and the elastomer is in physicaland electrical contact with the conductive layer.
 4. The electricaltermination of claim 1, wherein the opening is configured to reduce insize when the first and second conductive ground shield portions arelatched to one another and enclose the elastomer.
 5. The electricaltermination of claim 1, wherein, when the elastomer is compressed by theconductive ground shield, the elastomer exhibits a lower electricalresistance relative to when the elastomer is uncompressed.
 6. Theelectrical termination of claim 1, wherein the plurality of conductiveparticulates form a conductive path between an outer surface of theelastomer and an inner surface of the opening.
 7. The electricaltermination of claim 1, wherein, when the first and second conductiveground shield portions are latched to one another and enclose theelastomer, the cable makes electrical connection with the conductiveground shield with an electrical resistance of less than 100 Ohms. 8.The electrical termination of claim 1, wherein the elastomer comprisesat least one material selected from the group consisting of a highconsistency rubber (HCR), a fluorosilicone rubber (FSR) and a liquidsilicone rubber (LSR).
 9. The electrical termination of claim 1, whereinthe cable is a twin-ax cable without a drain wire.
 10. The electricaltermination of claim 1, wherein the opening has a width between 0.5 mmand 5 mm.
 11. The electrical termination of claim 10, wherein theopening has a height between 0.5 mm and 5 mm.
 12. The electricaltermination of claim 1, wherein the elastomer has a width between 1 mmand 20 mm.
 13. The electrical termination of claim 12, wherein theelastomer has a height between 1 mm and 20 mm.
 14. A method forterminating a cable, comprising: extruding a conductive, compressiblematerial with an opening formed therethrough; obtaining a conductive,compressible member by slicing a segment of the extruded conductive,compressible material; stripping a portion of the cable to expose aconductive layer of the cable; inserting the cable through the openingof the conductive, compressible member so that the conductive,compressible member overlaps with the exposed conductive layer; andpressing a conductive ground shield against the conductive, compressiblemember, wherein pressing the conductive ground shield against theconductive, compressible member comprises latching a first portion ofthe conductive ground shield to a second portion of the conductiveground shield.
 15. The method of claim 14, wherein the conductive,compressible material comprises an elastomer having a plurality ofconductive particulates embedded therein.
 16. The method of claim 14,wherein the cable comprises a single pair of signal conductors.
 17. Themethod of claim 16, wherein the opening is sized to accommodate a singlecable.
 18. The method of claim 14, wherein pressing the conductiveground shield against the conductive, compressible member results in anelectrical resistance between the conductive ground shield and the cableof less than 100 Ohms.
 19. The method of claim 14, wherein pressing theconductive ground shield against the conductive, compressible membercauses a reduction in a size of the opening.
 20. The method of claim 14,wherein slicing a segment of the extruded conductive, compressiblematerial comprises slicing a segment of 0.5 mm to 10 cm in length.
 21. Acable assembly comprising: a cable comprising an end; and an electricaltermination comprising: a conductive ground shield comprising first andsecond conductive ground shield portions having respective latches; andan elastomer comprising an opening therethrough and comprising aplurality of conductive particulates embedded therein, the elastomerbeing disposed between the first and second conductive ground shieldportions with the end of the cable passing through the opening, whereinthe elastomer, in an uncompressed state, has a region that is wider thana separation between the first and second conductive ground shieldportions, wherein, when the first and second conductive ground shieldportions are latched to one another and enclose the elastomer, theelastomer presses against the end of the cable.
 22. The cable assemblyof claim 21, wherein the end of the cable comprises an exposedconductive layer surrounding, at least in part, signal conductors, andthe elastomer is in physical and electrical contact with the conductivelayer.
 23. The cable assembly of claim 21, wherein the conductive groundshield individually encloses the cable, and wherein the cable comprisesa single pair of signal conductors.
 24. The cable assembly of claim 21,wherein the opening is configured to reduce in size when the first andsecond conductive ground shield portions are latched to one another andenclose the elastomer.
 25. The cable assembly of claim 21, wherein, whenthe elastomer is compressed by the conductive ground shield, theelastomer exhibits a lower electrical resistance relative to when theelastomer is uncompressed.
 26. The cable assembly of claim 21, wherein,when the first and second conductive ground shield portions are latchedto one another and enclose the elastomer, the cable makes electricalconnection with the conductive ground shield with an electricalresistance of less than 100 Ohms.
 27. The cable assembly of claim 21,wherein the cable is a twin-ax cable without a drain wire.